Various methods are known in the art for manufacturing high strength composite fiber tubular members. Many of these methods involve the use of a filament winding apparatus that is typically complex and costly, as well as limited in manufacturing capacity. U.S. Pat. No. 4,172,175 to Pearson and U.S. Pat. No. 4,273,601 to Weingart are examples of prior art filament winding tube manufacturing processes.
Additionally, methods of manufacturing tubular members using a conveying sheet disposed around a mandrel have been developed to obviate the need for costly winding equipment. U.S. Pat. No. 4,923,541 to Burger, incorporated herein by reference, discloses a method and apparatus for manufacturing composite tubes comprising wrapping various material layers around a mandrel utilizing a conveying sheet to accurately and evenly wrap said layers.
One difficulty with the prior art methods and the tubes produced thereby is that the composite fiber layers wrapped around the mandrel typically have seams that are generally parallel to a longitudinal axis of the mandrel. Furthermore, the fibers inherent in a wide variety of composite materials are often oriented generally parallel to the longitudinal axis of the mandrel. This arrangement of seams and composite fibers causes inherent weak points along the longitudinal seams, particularly in composite tubes that are subject to repeated impact, such as those used in the manufacture of baseball bats and the like.
Accordingly, there is a need in the art for a multi-layer composite fiber tubular member and a method of making such a tube that is devoid of longitudinal seams along its length.